SELF-QUADPLEXING SLOT ANTENNA FOR S- AND C-BAND APPLICATIONS

Abstract

This paper demonstrates a novel kind of cavity-backed self-quadplexing slot antenna for S- and C-band applications. The proposed antenna consists of four distinct U-shaped slots of different lengths and produces quad frequency bands for wireless communication systems. These slots are excited through separate and orthogonally placed 50 Ω micro-strip feed lines and generate four distinct operating bands at 3.2, 4.1, 5.8, and 7.2 GHz. Due to the perturbation of the different U-shaped slots over a substrate-integrated waveguide cavity with defined positions, the high intrinsic port isolation value is better than 30.5 dB. Thus, the proposed unique antenna structure combines the four independent operating bands with minimum mutual coupling and negligible interference among the input ports, showing the antenna's self-quadplexing feature. The proposed antenna also has frequency tunability with unidirectional radiation patterns and gains of 5.8, 5.4, 4.01, and 3.47 dBi at corresponding operated frequencies. The cross polarization is below 17.3 dB and the front-to-back ratio is higher than 21.5 dB at all operating quad bands. Good agreement was obtained between the simulated |S| parameter and equivalent circuit model results.